Fire and herbivory drive fungal and bacterial communities through distinct above- and belowground mechanisms.

Fire and herbivory are important natural disturbances in grassy biomes. Both drivers are likely to influence belowground microbial communities but no studies have unravelled the long-term impact of both fire and herbivory on bacterial and fungal communities. We hypothesized that soil bacterial communities change through disturbance-induced shifts in soil properties (e.g. pH, nutrients) while soil fungal communities change through vegetation modification (biomass and species composition). To test these ideas, we characterised soil physico-chemical properties (pH, acidity, C, N, P and exchangeable cations content, texture, bulk density, moisture), plant species richness and biomass, microbial biomass and bacterial and fungal community composition and diversity (using 16S and ITS rRNA amplicon sequencing, respectively) in six long-term (18 to 70 years) ecological research sites in South African savanna and grassland ecosystems. We found that fire and herbivory regimes profoundly modified soil physico-chemical properties, plant species richness and standing biomass. In all sites, an increase in woody biomass (ranging from 12 to 50%) was observed when natural disturbances were excluded. The intensity and direction of changes in soil properties were highly dependent on the topo-pedo-climatic context. Overall, fire and herbivory shaped bacterial and fungal communities through distinct driving forces: edaphic properties (including Mg, pH, Ca) for bacteria, and vegetation (herbaceous biomass and woody cover) for fungi. Fire and herbivory explained on average 7.5 and 9.8% of the fungal community variability, respectively, compared to 6.0 and 5.6% for bacteria. The relatively small changes in microbial communities due to natural disturbance is in stark contrast to dramatic vegetation and edaphic changes and suggests that soil microbial communities, having evolved with disturbance, are resistant to change. This represents both a buffer to short-term anthropogenic-induced changes and a restoration challenge in the face of long-term changes.

Acute stress alters individual risk taking in a time-dependent manner and leads to anti-social risk.

Decision-making processes can be modulated by stress, and the time elapsed from stress induction seems to be a crucial factor in determining the direction of the effects. Although current approaches consider the first post-stress hour a uniform period, the dynamic pattern of activation of the physiological stress systems (i.e., the sympathetic nervous system and hypothalamic-pituitary-adrenal axis) suggests that its neurobehavioural impact might be heterogeneous. Here, we evaluate economic risk preferences on the gain domain (i.e., risk aversion) at three time points following exposure to psychosocial stress (immediately after, and 20 and 45 min from onset). Using lottery games, we examine decisions at both the individual and social levels. We find that risk aversion shows a time-dependent change across the first post-stress hour, evolving from less risk aversion shortly after stress to more risk averse behaviour at the last testing time. When risk implied an antisocial outcome to a third party, stressed individuals showed less regard for this person in their decisions. Participants' cortisol levels explained their behaviour in the risk, but not the antisocial, game. Our findings reveal differential stress effects in self- and other-regarding decision-making and highlight the multidimensional nature of the immediate aftermath of stress for cognition.

Open vs laparoscopic repair of perforated peptic ulcer.

BACKGROUND: Most studies have found that the only advantage to the laparoscopic treatment of perforated peptic ulcer is a reduced need for postoperative analgesia. Therefore, we set out to assess the short-term outcome of open (OR) versus laparoscopic (LR) repair of perforated peptic ulcer. METHODS: A total of 62 consecutive OR patients were compared with a concurrent cohort of 17 diagnosis-matched LR controls treated at the same hospital between 1991 and 1996. RESULTS: The OR and LR patients were comparable for age, weight, American Society of Anesthesiologists (ASA) grade, Acute Physiology and Chronic Health Evaluation (APACHE II) score, Boey score, ulcer site, Mannheim Peritonitis Index (MPI), delay of surgery, Helicobacter pylori infection, nonsteroidal antiinflammatory drug (NSAID) intake, and previous abdominal surgery. More LR than OR patients were operated on by staff surgeons (chi2 = 46.9, 1 d.f., p << 0.01). Mortality (OR: 12, LR: two), morbidity (OR: eight, LR: two), estimated blood loss (OR: 120 ml, LR: 95 ml), solid food intake resumption (OR: 5 days, LR 4 days), NSAID consumption (OR: 2,225 mg, LR: 1,815 mg), delayed gastric emptying (OR: two, OR: one), and hospital stay (OR: 9 days, LR: 7 days) were not significantly different for the two groups. Four LR patients (23. 5%) were converted to OR due to failure to progress (n = 3) or posterior perforation (n = 1). Operating time was shorter in OR patients (65 min versus 92 min, p << 0.01). LR patients had reduced opioid consumption (256 mg versus 134 mg, p << 0.01). One LR and 16 OR patients were lost to follow-up. Median follow-up was 14 months (range, 2-55) and 18 months (range, 1-62) in OR and LR patients, respectively. There were more LR than OR patients with Visick score I (p = 0.002) and more OR than LR patients with Visick score II (p = 0.0001). Scores III and IV did not differ significantly. CONCLUSION: The laparoscopic repair of perforated peptic ulcer does not yield any additional benefits over the open repair.

Open versus laparoscopic gastrojejunostomy for palliation in advanced pancreatic cancer.

To assess short-term outcome of open (OGJ) versus laparoscopic (LGJ) gastrojejunostomy in palliation of gastric outlet obstruction (GOO) caused by advanced pancreatic cancer, 22 OGJ patients were compared with 9 diagnosis-matched LGJ controls operated on at the same hospital between 1991 and 1996. Patients undergoing OGJ and LGJ were comparable for age, gender, weight, American Society of Anesthesiologists grading, and previous extensive abdominal surgery, but not for gastroenterostomy performed as a prophylactic procedure (9 vs. 0, respectively). Mortality (5 vs. 1, p = 1.5), overall morbidity (9 vs. 3, p = 0.42), operating time (113.6 +/- 24.5 minutes vs. 125 +/- 15.2 minutes, p < 0.5), time to oral solid food intake (7.2 +/- 0.9 days vs. 5.3 +/- 1.3 days, p < 0.5), nonsteroidal anti-inflammatory drug consumption (7,563.6 +/- 3,381.3 mg vs. 2,044 +/- 673 mg, p < 0.5), opioid consumption (688.5 +/- 258.6 mg vs. 2,910.5 +/- 2,659.9 mg, p < 0.5), delayed-return gastric emptying (5 vs. 1, p = 0.12), postoperative hospital stay (14.6 +/- 1.9 days vs. 10.1 +/- 1.8 days, p < 0.5), survival (5.7 +/- 0.8 months vs. 4.6 +/- 0.6 months, p < 0.5), and further hospital stay before death (9.8 +/- 3.3 days vs. 11.6 +/- 3.4 days, p > 0.5) were not significantly different in 22 OGJ and 9 LGJ patients, respectively. Estimated blood loss was significantly lower in LGJ patients (270.2 +/- 45.8 ml vs. 66 +/- 15.7 ml, p < 0.01). When 13 of 22 patients undergoing OGJ for treatment were compared with 9 LGJ patients, only estimated blood loss (p < 0.01) and hospital stay (p < 0.05) were significantly reduced in LGJ patients. Recurrent GOO before death occurred in one patient (1 of 22, 4.5%) 9 months after OGJ. LGJ for palliative treatment of GOO in advanced pancreatic cancer offered (in spite of the learning curve) reduced estimated blood loss and hospital stay when compared with OGJ.

[Transanal endoscopic microsurgery]. / Transanal endoskopisk mikrokirurgi.

Transanal endoscopic microsurgery was introduced by Buess and co-workers in 1984 for transanal removal of tumours up to 20 cm above anus. In the present study, 18 transmural and two mucosal resections were performed for rectal adenomas (16) and early rectal cancer (4). Median operation time was 85 minutes (55-140 minutes) and the median postoperative stay in hospital was 3 days (1-5). All tumours were removed radically and in none was there tumour involvement of the resection margin. There were no serious complications. After a median observation time of 10 months (1-17 months) there have been no recurrences. Functional results are excellent; none of the patients have developed incontinence. It is concluded that transanal endoscopic microsurgery (TEM) is an adequate method for removal of benign rectal tumours and, in selected cases, early rectal cancer.

Perianal fistulas: use of MR imaging for diagnosis.

PURPOSE: To evaluate use of magnetic resonance (MR) imaging with saline solution as contrast agent in diagnosis of perianal fistulous disease. MATERIALS AND METHODS: Spin-echo intermediate-, T2-, and T1-weighted images were obtained before and after instillation of saline solution into anal fistulas in 12 of 16 consecutive patients. In four patients without secretory fistulas, images were obtained without contrast enhancement. RESULTS: Fistulous tracts were found in 13 patients, fluid cavities in 13, secondary fibrotic tracts in two, and normal perirectal tissue in one. The extent of fistulas and fluid collections was better delineated or more conspicuous on contrast-enhanced images in eight and 10 examinations, respectively, in part due to expansion of collapsed portions of the fistulous system. T2-weighted images were sufficient for diagnosis. CONCLUSION: MR imaging with saline solution as contrast agent may improve visualization of fistulas and their relationship to normal anatomic structures in patients with complex fistulous systems with relatively sparse secretion.

Cholescintigraphy in the diagnosis and follow up of hepatobiliary injury.

Cholescintigraphy is a simple and reliable way of detecting a liver injury accompanied by biliary leakage and is also well suited to assess the effectiveness of treatment and to follow recovery. To emphasize these points, a case report of a patient suffering from a severe injury to the liver is presented.